With increasing awareness of mental health issues and knowledge of the nervous system and neuropharmacology, progress has been made in the treatment of common psychiatric disorders, including dementia, depression, and apathy. There is however still a need for effective therapies that can stop, slow, reverse, or prevent the indications of dementia, depression, and apathy that accompany diverse mental disorders. There is also a need to refine and further characterise the diagnostic criteria that may be used to differentiate patients amenable to alternative therapeutic regimens.